Prospective evaluation of the ultrasound appearance of the endometrium in a cohort of 1,186 infertile women

Walking on thin endometrium

PURPOSE OF REVIEW

Endometrial thickness has been regarded a predictor of success in assisted reproductive technology cycles and it seems a common practice to cancel embryo transfer when it is below a cut-off. However, various cut-offs have been proposed without a causal relationship between endometrial thickness and embryo implantation being established, casting doubt on the current dogma.

RECENT FINDINGS

Methodological limitations of the available studies on endometrial thickness are increasingly recognized and better designed studies do not demonstrate a cut-off value which requires cancelling an embryo transfer.

SUMMARY

Endometrium is important for implantation and a healthy pregnancy; however, ultrasound measured thickness does not seem to be a good marker of endometrial function.

The impact of estradiol supplementation on endometrial thickness and intrauterine insemination outcomes

The impact of estrogen supplementation during the follicular/proliferative phase on the endometrial lining thickness (EMT) prior to intrauterine insemination (IUI) remains largely unstudied. Our study examined changes in EMT and rates of clinical pregnancy, miscarriage, and live birth for all patients who completed an IUI cycle at Stanford Fertility Center from 2017-2023 (n = 2281 cycles). Cycles with estradiol supplementation (n = 309) were compared to reference cycles without supplementation (n = 1972), with the reference cohort further categorized into cycles with a pre-ovulatory EMT of < 7 mm ("thin-lining", n = 536) and ≥ 7 mm ("normal-lining", n = 1436). The estradiol group had a statistically significant greater change in EMT from baseline to ovulation compared to the thin-lining reference groups (2.4 mm vs 1.9 mm, p < =0.0001). Similar rates of clinical pregnancy and live birth were observed. After adjusting for age, BMI, race/ethnicity, infertility diagnosis, and EMT at trigger, the estradiol cohort had a significantly increased odds of miscarriage versus the entire reference cohort (2.46, 95 % confidence interval [1.18, 5.14], p = 0.02). Thus, although estradiol supplementation had a statistically significant increase in EMT compared to IUI cycles with thin pre-ovulatory EMT (<7 mm), this change did not translate into improved IUI outcomes such as increased rates of clinical pregnancy and live birth or decreased rate of miscarriage. Our study suggests that supplemental estradiol does not appear to improve IUI outcomes.

When the Embryo Meets the Endometrium: Identifying the Features Required for Successful Embryo Implantation

Evaluation of the optimal number of embryos, their quality, and the precise timing for transfer are critical determinants in reproductive success, although still remaining one of the main challenges in assisted reproduction technologies (ART). Indeed, the success of in vitro fertilization (IVF) treatments relies on a multitude of events and factors involving both the endometrium and the embryo. Despite concerted efforts on both fronts, the overall success rates of IVF techniques continue to range between 25% and 30%. The role of the endometrium in implantation has been recently recognized, leading to the hypothesis that both the "soil" and the "seed" play a central role in a successful pregnancy. In this respect, identification of the molecular signature of endometrial receptivity together with the selection of the best embryo for transfer become crucial in ART. Currently, efforts have been made to develop accurate, predictive, and personalized tests to identify the window of implantation and the best quality embryo. However, the value of these tests is still debated, as conflicting results are reported in the literature. The purpose of this review is to summarize and critically report the available criteria to optimize the success of embryo transfer and to better understand current limitations and potential areas for improvement.

Can endometrial compaction predict live birth rates in assisted reproductive technology cycles? A systematic review and meta-analysis

PURPOSE

Endometrial compaction (EC) is defined as the difference in endometrial thickness from the end of the follicular phase to the day of embryo transfer (ET). We aimed to determine the role of EC in predicting assisted reproductive technology (ART) success by conducting a meta-analysis of studies reporting the association between EC and clinical outcomes of ART.

METHODS

MEDLINE via PubMed, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from the date of inception to May 19, 2023. The primary outcome was live birth rate (LBR) per ET. Secondary outcomes were live birth or ongoing pregnancy per ET, ongoing pregnancy per ET, clinical pregnancy per ET, and miscarriage per clinical pregnancy.

RESULTS

Fifteen studies were included. When data from all studies reporting live birth were pooled, overall LBR rates were comparable in cycles showing EC or not [RR = 0.97, 95%CI = 0.92 to 1.02; 10 studies, 11,710 transfer cycles]. In a subgroup of studies that included euploid ET cycles, a similar LBR for patients with and without EC was noted [RR = 0.99, 95%CI = 0.86 to 1.13, 4 studies, 1172 cycles]. The miscarriage rate did not seem to be affected by the presence or absence of EC [RR = 1.06, 95%CI = 0.90 to 1.24; 12 studies].

CONCLUSION

The predictive value of EC in determining LBR is limited, and assessment of EC may no longer be necessary, given these findings.

TRIAL REGISTRATION

PROSPERO CRD42023410389.

A critical appraisal of studies on endometrial thickness and embryo transfer outcome

A receptive endometrium is required for successful embryo implantation. Endometrial thickness, as measured by ultrasonography, is the most commonly used marker of endometrial receptivity in assisted reproductive technology cycles. Several factors simultaneously affect both endometrial thickness and probability of live birth, including age, oestradiol concentration and oocyte number, among others. Most of the studies investigating a relationship between endometrial thickness and embryo transfer outcomes are retrospective and do not adequately address confounding factors, in addition to other limitations. Despite multiple meta-analyses and studies with large numbers of cycles, controversy still exists. The difference between the results from prospective and retrospective studies is also striking. This article presents a critical appraisal of the studies on endometrial thickness and embryo transfer outcomes in order to highlight methodological issues and how they can be overcome in future studies. Currently available evidence does not seem to support a modification of management just because endometrial thickness is below an arbitrary threshold.

Effect of the endometrial thickness on the live birth rate: insights from 959 single euploid frozen embryo transfers without a cutoff for thickness

OBJECTIVE

To investigate whether endometrial thickness (ET) independently affects the live birth rate (LBR) after embryo transfer.

DESIGN

Retrospective study.

SETTING

Private assisted reproductive technology center.

PATIENT(S)

A total of 959 single euploid frozen embryo transfers.

INTERVENTION(S)

Vitrified euploid blastocyst transfer.

MAIN OUTCOME MEASURE(S)

Live birth rate per embryo transfer.

RESULT(S)

The conditional density plots did not demonstrate either a linear relationship between the ET and LBR or a threshold below which the LBR decreased perceivably. Receiver operating characteristic curve analyses did not suggest a predictive value of the ET for the LBR. The area under the curve values were 0.55, 0.54, and 0.54 in the overall, programmed, and natural cycle transfers, respectively. Logistic regression analyses with age, embryo quality, day of trophectoderm biopsy, body mass index, and ET did not suggest an independent effect of the ET on the LBR.

CONCLUSION(S)

We did not identify a threshold of the ET that either precluded live birth or under which the LBR decreases perceivably. Common practice of cancelling embryo transfers when the ET is <7 mm may not be justified. Prospective studies, in which the management of the transfer cycle would not be altered by ET, would provide higher-quality evidence on the subject.

Impact of prolonged one or more natural menstrual cycles on the outcomes of ovulation induction intrauterine artificial insemination pregnancy: a single-centre, retrospective study in China

OBJECTIVES

We determined if the time interval between two ovulation induction intrauterine artificial insemination (IUI) treatment cycles should be extended by one or more natural menstrual cycles in patients undergoing successive cycles of ovulation stimulation, and whether this affects clinical pregnancy rate (CPR).

DESIGN

This study was conducted on infertility patients treated under the ovulation induction programme IUI in a large reproductive centre in China. Study participants were assigned into continuous and discontinuous groups. Differences in baseline clinical pregnancy and abortion rates were compared between the groups. A multivariate logistic model was used to evaluate the effects of time interval on clinical pregnancy outcomes.

SETTING

Reproductive Centre of Maternal and Child Health Hospital of Lianyungang city.

INTERVENTIONS

None.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was CPR, the secondary outcome measure was the abortion rate.

RESULTS

A total of 550 IUI treatment cycles involving 275 couples were included in this study. Differences in CPR and abortion rate between the groups were not significant (20.5% vs 21.9% and 27.8% vs 22.0%, p≥0.05). Stratified analyses based on infertility factors did not reveal any significant differences in pregnancy and abortion rates between the groups (p≥0.05). Multivariate analysis showed that increased endometrial thickness correlates with CPR (OR 1.205, 95% CI 1.05 to 1.384, p=0.008). Compared with primary infertility, secondary infertility significantly correlated with improved CPR (OR 2.637, 95% CI 1.313 to 5.298, p=0.006). The effects of time interval between the first two ovulation induction IUI treatment cycles on clinical pregnancy were not significant (OR 1.007, 95% CI 0.513 to 1.974, p=0.985).

CONCLUSIONS

Longer time intervals between the first two ovulation induction IUI treatment cycles did not significantly improve CPR. Therefore, in the absence of clear clinical indications, it may not be necessary to deliberately prolong the interval between two ovulation induction IUI treatment cycles.

Influence of Maternal Age on the Relationship Between Endometrial Thickness and Ongoing Pregnancy Rates in Frozen-Thawed Embryo Transfer Cycles: A Retrospective Analysis of 2,562 Cycles

Background

In frozen-thawed embryo transfer (FET) cycles, endometrial thickness (EMT) has been used routinely as the main clinical monitoring index. However, the current findings are conflicting.

Method

This was a single-center retrospective study of 2,054 couples (2,562 cycles) who underwent FET (including cleavage stage embryos and blastocysts) between January 2017 and August 2020 in the reproductive centers of First Affiliated Hospital of Xinjiang Medical University. The primary outcome measure was the ongoing pregnancy rate (OPR); the secondary outcome was the clinical pregnancy rate.

Results

After stratified analysis and adjusting for confounders such as maternal age, duration of infertility, number of high-quality embryos transferred, endometrial preparation protocol, number of transfer cycles, and stages of embryo transferred, we found a curvilinear relationship between EMT and the OPR in women < 35 years of age. For women with EMT ≤ 8 mm, the OPR increased by 150% for cleavage stage embryo transfer for every 1 mm increase in the EMT; similarly, it increased by 97% for blastocyst stage FET. However, there was a linear relationship between EMT and OPR in women aged ≥ 35 years. When blastocysts were transferred, for every 1 mm increase in the EMT the OPR increased significantly by 12%. But OPR after frozen-thawed cleavage stage embryos transfer did not increase significantly with increased EMT.

Conclusions

Our study showed that the OPR increased significantly with increased EMT between young women aged < 35 years with EMT ≤ 8 mm and older women who underwent transfer of blastocysts.

Single-cell transcriptome analysis uncovers the molecular and cellular characteristics of thin endometrium

Infertility is a social and medical problem around the world and the incidence continues to rise. Thin endometrium (TE) is a great challenge of infertility treatment, even by in vitro fertilization and embryo transfer. It is widely believed that TE impairs endometrium receptivity. However, only a few studies have explained the molecular mechanism. Herein, in order to reveal the possible mechanism, we sampled endometrium from a TE patient and a control volunteer and got a transcriptomic atlas of 18 775 individual cells which was constructed using single-cell RNA sequencing, and seven cell types have been identified. The cells were acquired during proliferative and secretory phases, respectively. The proportion of epithelial cells and stromal cells showed a significant difference between the TE group and the control group. In addition, differential expressed genes (DEGs) in diverse cell types were revealed, the enriched pathways of DEGs were found closely related to the protein synthesis in TE of both proliferative and secretory phases. Some DEGs can influence cell-type ratio and impaired endometrial receptivity in TE. Furthermore, divergent expression of estrogen receptors 1 and progesterone receptors in stromal and epithelial cells were compared in the TE sample from the control. The cellular and molecular heterogeneity found in this study provided valuable information for disclosing the mechanisms of impaired receptivity in TE.

Frozen Blastocyst Embryo Transfer: Comparison of Protocols and Factors Influencing Outcome

Background: Various factors, including treatment protocols, can influence the outcomes of frozen embryo transfers (FETs). The study objectives were to compare different endometrial preparation protocols of FET cycles and to evaluate the factors, including the endometrial thickness (ET), that affect outcomes. Methods: This observational cohort study involved 5037 women undergoing FETs at eight tertiary clinics in the UK between January 2016 and March 2019. The endometrial preparation protocols used were natural cycle (NC-FETs), artificial hormone support cycle with oestradiol valerate but without pituitary downregulation (AC-FETs) and artificial hormone support cycle with agonist downregulation (ACDR-FETs). Results: The mean (±SD) ages across NC-FET, AC-FET and ACDR-FET groups were 36.5 (±4.2), 35.9 (±5.0) and 36.4(±4.9) years, respectively. LBRs were comparable (40.7%, 175/430; 36.8%, 986/2658; and 36.7%, 716/1949, respectively) across the three groups. Clinical pregnancy, implantation, multiple pregnancies, miscarriage and ectopic pregnancy rates were also similar. In the regression analysis of variables including age, duration of infertility, number of embryos transferred, protocol type and endometrial thickness, age was the only significant predictor of LBRs, although its predictive ability was poor (AUC: 0.55). With the overall LBR of the study population being 37.1%, the post-test probability of a live birth at an ET of <5 mm was 0%, and at 5–5.9, 6–6.9, 7–7.9 and 8–8.9 mm, the probabilities were 16.7%, 33.8%, 36.7% and 37.7%, respectively. The LBR remained above 35% up to the 14–14.9 mm range and then declined gradually to 23% for the 17–25 mm range. Conclusions: The FET outcomes were similar for the three protocols used for endometrial preparation. The protocol type and endometrial thickness were not predictive of FET outcomes; age was the only predictive variable, despite its low predictive ability.

Nomogram to predict an endometrial thickness above 7.5 mm in the frozen embryo transfer cycle of women with a thin endometrium

RESEARCH QUESTION

Which characteristics of patients with a thin endometrium (endometrial thickness [EMT] ≤7.5 mm on human chorionic gonadotrophin [HCG] trigger day) suggest the possibility of an EMT >7.5 mm in the subsequent frozen cycle?

DESIGN

Data were collected from the university-affiliated Centre for Reproductive Medicine between January 2013 and September 2019. Multivariable logistic regression was used to generate the final prediction model and construct the nomogram. Model performances were quantified by discrimination and calibration.

RESULTS

The predictive variables that entered the final model were: hysteroscopic adhesiolysis history, polycystic ovary syndrome status, application of clomiphene in the ovarian stimulation process, the ovarian stimulation protocol and the endometrial preparation protocol. The receiver operating characteristic (ROC) curve for the final model and validation cohort was 0.760 (95% confidence interval [CI] 0.722-0.797) and 0.713 (95% CI 0.664-0.759), respectively. Discrimination performed well in both the modelling and validation cohorts.

CONCLUSIONS

In women with a thin endometrium (EMT ≤7.5 mm on HCG trigger day), the absence of a hysteroscopic adhesiolysis history, the presence of polycystic ovary syndrome, the application of clomiphene in the ovarian stimulation process, the application of a gonadotrophin-releasing hormone agonist short protocol, mild stimulation protocol, natural cycle protocol, and natural cycle for endometrial preparation are prognostic for an increased possibility of an EMT >7.5 mm in the subsequent frozen cycle.

3D stem cell-laden artificial endometrium: successful endometrial regeneration and pregnancy

Thin endometrium lining or severe endometrial injury which may occur during artificial abortion can cause defective endometrial receptivity and subsequent infertility. Therefore, much effort has been devoted toward regenerating thin or damaged endometrial lining by applying multiple types of stem cells. Even though there are some positive preliminary outcomes, repairing the injured endometrium with stem cells is considerably challenging, due to the lack of an adequate microenvironment for the administrated stem cells within the tissues and subsequent poor therapeutic efficiency. In this context, as an alternative, we fabricated a 3D stem cell-laden artificial endometrium by incorporating several biodegradable biomaterials (collagen and hyaluronic acid) and multiple cellular components of endometrium (endometrial stem cells, stromal cells, and vessel cells) to properly recapitulate the multicellular microenvironment and multilayered structure. Agarose was used as an inert filler substrate to enhance the mechanical integrity of the three-layered artificial endometrium. Various mechanical characteristics, such as morphology, compression properties, swelling, and viscosity, have been evaluated. Various biological features, such as steroid hormone responsiveness, specific endometrial cell-surface marker expressions, and the secretion of multiple growth factors and steroid hormones, as well as the viability of encapsulated endometrial cells are relatively well maintained within the artificial endometrium. More importantly, severe tissue injuries were significantly relieved by transplanting our 3D artificial endometrium into endometrial ablation mice. Remarkably, artificial endometrium transplantation resulted in a successful pregnancy with subsequent live birth without any morphological or chromosomal abnormalities.

Factors Affecting Artificial Insemination Pregnancy Outcome

Objective

The aim of the present study was to explore related clinical pregnancy outcome factors in intrauterine insemination (IUI).

Materials and Methods

The clinical data of 3984 IUI cycles in 1862 couples experiencing infertility who attended the Reproductive Center of Binzhou Medical University Hospital between July 2006 and July 2017 were retrospectively analyzed. Female and male patient age, endometrial thickness (EMT), the post-wash total motile sperm count (PTMC), artificial insemination timing, insemination frequency, and ovarian stimulation protocols were compared between the study’s pregnant group and non-pregnant group in order to explore any correlation.

Results

There were statistically significant differences in female and male age, EMT, artificial insemination timing, insemination frequency, and ovarian stimulation protocols between the two groups (p < 0.05). The clinical pregnancy rate was significantly higher in ovarian stimulation cycles than in natural cycles (21.2% and 11.6%, respectively; p < 0.01), the clinical pregnancy rate was significantly higher in double IUI than in single IUI (17.8% and 12.1%, respectively; p < 0.01), and EMT was significantly greater in the pregnant group than in the control group (p < 0.05). However, the differences in clinical pregnancy rates among the PTMC groups were not statistically significant (14.8%, 14.4%, 17.3%, and 17.3%, respectively; p > 0.05).

Conclusion

The results of the present study demonstrate that the clinical IUI pregnancy rate is correlated with the factors of female age, male age, EMT, artificial insemination timing, insemination frequency, and ovarian stimulation protocols; the ovarian stimulation protocol can noticeably improve the patient pregnancy outcome. Furthermore, compared with single IUI, double IUI can significantly increase the clinical pregnancy rate.

The strain rate of endometrium measured by real-time sonoelastography as a predictive marker for pregnancy in gonadotropin stimulated intrauterine insemination cycles

AIM

Sonoelastography is an imaging technique that measures tissue strain quantitatively. This study aims to investigate whether the strain rate of endometrium measured by elastography can predict pregnancy after intrauterine insemination (IUI).

METHODS

This study examined 197 gonadotropin-stimulated IUI cycles of 148 women diagnosed with unexplained infertility from February 2019 to November 2020. Endometrial thickness, pattern, and strain rate were measured by transvaginal ultrasonography immediately before the insemination. The endometrium and the parametrial tissue were selected for regions of interest, and the strain rate was calculated. The measurements were analyzed concerning the IUI outcome.

RESULTS

Of the 197 IUI cycles, the pregnancy rate was 15.20% (n = 30), and ongoing pregnancy rate was 12.2% (n = 24). The mean strain rates were not different between pregnant and nonpregnant groups (2.68 ± 1.28 vs. 2.81 ± 1.32, p = 0.651). Strain rate was not predictive for pregnancy, shown by receiver operating characteristic curve analysis; the area under the curve was 0.526 (95% CI 0.413-0.639; p = 0.649). Pregnancy rates were significantly affected by the women's age and the inseminated sperm count. In multiple logistic regression analysis, the other parameters, including body mass index, anti-Müllerian hormone, endometrial thickness, endometrial strain rate, and echogenic endometrial pattern, did not significantly change the odds ratio of pregnancy.

CONCLUSION

The endometrial strain rate does not significantly affect the pregnancy rates in gonadotropin stimulated IUI cycles. It appears that strain rate does not predict IUI outcome. More research is needed to evaluate the usefulness of sonoelastography in infertility treatments.

Endometrial thickness following early miscarriage in IVF patients - is there a preferred management approach?

BACKGROUND

Endometrial thickness (ET) has previously been shown to positively correlate with implantation and clinical pregnancy rates. Pregnancies achieved using in-vitro fertilization (IVF) technique are prone to higher rates of early miscarriage. The aim of this study was to compare the effects of expectant management, medical treatment (Misoprostol) and dilation and curettage (D&C) for early miscarriage following IVF cycles on the subsequent cycle outcomes - endometrial thickness and reproductive outcomes.

METHODS

A retrospective cohort study of women who underwent embryo transfer, conceived and had first trimester miscarriage with at least one subsequent embryo transfer. ET measurements during fresh or frozen-thawed IVF cycles were assessed for each patient. Comparisons of ET differences between the miscarriage and the subsequent cycles, as well as reproductive outcomes, were performed according to the initial miscarriage management approach.

RESULTS

A total of 223 women were included in the study. Seventy-eight women were managed conservatively, 61 were treated with Misoprostol and 84 women underwent D&C. Management by D&C, compared to conservative management and Misoprostol treatment was associated with higher prevalence of a significant (> 2 mm) ET decrease (29.8%% vs. 14.1and 6.6%, respectively; p < .001) and was the only approach associated with a significant increase in the rates of ET under 7 and 8 mm in the following cycle (p = 0.006 and 0.035; respectively). Clinical pregnancy rates were significantly lower following D&C compared with conservative management and Misoprostol (16.7% vs. 38.5 and 27.9%, respectively; p = 0.008) as well as implantation rate (11.1% vs. 30.5.% and 17.7, respectively; p < 0.001).

CONCLUSION

Our data suggest that D&C management of a miscarriage is associated with decreased ET and higher rates of thin endometrium in the subsequent IVF cycle, compared with conservative management and Misoprostol treatment. In addition, implantation and pregnancy rates were significantly lower after D&C.

Effect of gonadotropins and endometrial thickness on pregnancy outcome in patients with unexplained infertility or polycystic ovarian syndrome undergoing intrauterine insemination

Objective

The purpose of this study was to investigate the effect of gonadotropin dose and endometrial thickness (EMT) on pregnancy outcome in patients undergoing intrauterine insemination (IUI).

Methods

We retrospectively analyzed data from 361 patients with unexplained infertility or polycystic ovarian syndrome (PCOS) who underwent 930 IUI cycles treated with gonadotropins. Then, we measured the effects of gonadotropins and EMT on the clinical pregnancy rate. Finally, we assessed the association of various doses of gonadotropins on EMT.

Results

The dose of gonadotropins given and thickness of the endometrium were higher in the pregnancy group than in the nonpregnancy group (636.0 vs. 600.0 IU for gonadotropin dose; 9.15 vs. 8.70 mm for EMT). Clinical pregnancy rates were significantly improved by increasing the dose of gonadotropins (9.1%, <450 IU; 16.2%, 450–599 IU; 18.6%, 600–749 IU, and 17.3%, ≥750 IU), or by increased EMT (0%, <5.0 mm; 12.2%, 5.0–6.9 mm; 15.5%, 7.0–14.0 mm; and 33.3%, >14.0 mm).

Conclusion

Increasing the dose of gonadotropins to stimulate one follicle to develop may benefit endometrial proliferation and improve IUI outcomes.

Endometrial thickness is not predictive for live birth after embryo transfer, even without a cutoff

OBJECTIVE

To investigate the predictive value of endometrial thickness (EMT) for live birth when a lower threshold of EMT is not employed for embryo transfer (ET).

DESIGN

Retrospective study SETTING: Academic assisted reproduction center PATIENT(S): All women who underwent fresh or frozen-thawed ET at the Koç University Hospital Assisted Reproduction Unit between October 2016 and August 2019 INTERVENTION(S): After ruling out endometrial pathology, blastocyst transfer was planned regardless of the EMT in the absence of increased serum progesterone level on the trigger day in fresh embryo transfer cycles or before commencing progesterone treatment in artificially prepared frozen-thawed ET cycles.

MAIN OUTCOME MEASURE(S)

The primary outcome was live birth. Live birth and miscarriage rates per ET were stratified according to fresh and frozen-thawed ET cycles for each millimeter of endometrial thickness. Receiver operator characteristic curve analyses were performed to evaluate the predictive value of EMT for live birth.

RESULT(S)

A total of 560 ET cycles, 273 fresh and 287 frozen-thawed, were included in the study. Relevant patient characteristics as well as EMTs were similar between women who achieved a live birth and those who did not after fresh or frozen-thawed ET. There was no linear association between EMT and live birth or miscarriage rates. Area under the curve values for EMT to predict live birth after fresh, frozen-thawed, and all ETs were 0.56, 0.47, and 0.52, respectively.

CONCLUSION(S)

Our results showed that the EMT was not predictive for live birth in either fresh or frozen-thawed ET cycles. Once intracavitary pathology and inadvertent progesterone exposure were excluded, women with thinner EMTs should not be denied their potential for live birth because it is comparable to that of those with thicker EMT.

Application of a Nomogram for Predicting the Risk of Subchorionic Hematoma in Early Pregnancy With In Vitro Fertilization-Embryo Transfer/Frozen Embryo Transfer

BACKGROUND

Subchorionic hematoma (SCH) is common in early pregnancy achieved by in vitro fertilization-embryo transfer/frozen embryo transfer (IVF-ET/FET), and is associated with adverse obstetric outcomes. However, there are no methods known to accurately predict the occurrence of SCH.

OBJECTIVE

To establish a nomogram prediction model for predicting the risk of SCH in early pregnancy with IVF-ET/FET and to analyze pregnancy outcomes of patients with SCH.

METHODS

Patients who underwent IVF-ET/FET treatment and were diagnosed with clinical pregnancy were enrolled in our study. A total of 256 patients with SCH were enrolled in the SCH group, and 526 patients without SCH in the control group. Logistic regression was used to screen risk factors for SCH, and the nomogram was developed according to the regression coefficient of relevant variables. Discrimination, effect, calibration, and the predictive model's clinical usefulness were assessed using the C-index, the area under the receiver operating characteristic standard curve, calibration plot, and decision curve analysis. Internal validation was assessed using bootstrapping validation. The effects of SCH on pregnancy outcomes were analyzed.

RESULTS

A multivariate logistic regression analysis showed that fresh embryo transfer, polycystic ovary syndrome, hydrosalpinx, and thin endometrium were risk factors affecting the occurrence of SCH. Based on the above factors, a predictive model for the risk of SCH was created. The model displayed good discrimination, with a C-index of 0.783 (95% confidence interval: 0.750-0.816), area under the receiver operating characteristic standard curve of 0.783, and good calibration. A high C-index value of 0.765 could still be reached in the interval validation. Decision curve analysis showed that the nomogram was clinically useful when the intervention was decided at the SCH possibility threshold of 4%-87%. For patients with successful deliveries, the occurrence of SCH did not influence the gestational weeks of delivery, mode of delivery, preterm birth, height, and weight of the newborn.

CONCLUSION

We screened the risk factors for SCH in patients who underwent IVF-ET/FET treatment. Successful establishment of a nomogram can effectively predict the occurrence of SCH. Furthermore, the incidence of miscarriage is higher in patients with SCH.

Endometrial thickness after ovarian stimulation with gonadotropin, clomiphene, or letrozole for unexplained infertility, and association with treatment outcomes

OBJECTIVE

To study the association of endometrial thickness (EMT) with live birth rates (LBR) in ovarian stimulation with intrauterine insemination (OS-IUI) treatments for unexplained infertility.

DESIGN

Prospective cohort analysis of the Reproductive Medicine Network's Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS) randomized controlled trial.

SETTING

Multicenter randomized controlled trial.

PATIENTS

A total of 868 couples with unexplained infertility (n=2,459 cycles).

INTERVENTIONS

OS-IUI treatment cycles (n = 2,459) as part of the AMIGOS clinical trial.

MAIN OUTCOME MEASURES

Live birth rates; unadjusted and adjusted risk ratios (RR) for live birth by EMT category, calculated using generalized estimating equations.

RESULTS

The overall mean EMT on day of human chorionic gonadotropin administration in cycles with a live birth was significantly greater than in those without. Compared to the referent EMT group of 9 to 12 mm, the unadjusted RR for live birth for the EMT groups of ≤5 and 6-8 were 0.48 and 0.92, respectively. The test for trend indicated evidence of decreasing LBR with decreasing EMT. After adjustment for ovarian stimulation medication, a linear trend was no longer supported. Stratified analyses revealed no differences in associations by treatment group.

CONCLUSIONS

In OS-IUI for unexplained infertility, higher LBR are observed with increasing EMT; however, EMT is not significantly associated with LBR when adjusted for OS treatment type. Appreciable LBR are seen at all EMT, even those of ≤5 mm, suggesting that OS-IUI cycles should not be canceled for thin endometrium.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01044862.

Association between endometrial thickness and neonatal outcomes in intrauterine insemination cycles: a retrospective analysis of 1,016 live-born singletons

BACKGROUND

Decreased endometrial thickness (EMT) has been suggested to be associated with reduced birthweight of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) newborns. Considering the differences in ovarian stimulation degree and laboratory procedures between IVF/ICSI and IUI treatment, we aim to investigate whether EMT has any influence on IUI infant outcomes as well.

METHODS

This was a retrospective cohort study of 1016 patients who had singleton livebirths after IUI treatment cycles from January 2008 to December 2018 at a tertiary-care academic medical center in China. Patients were categorized into three groups by the 10th and 90th percentile of peak EMT: ≤7.6, 7.7-13.0 and ≥ 13.1 mm. The primary outcomes of the study were preterm birth (PTB), low birthweight (LBW) and small-for-gestational age (SGA). Multiple regression analyses were performed after controlling for a variety of potential confounders.

RESULTS

No significant differences were found among the three groups in gestational age, birthweight and birthweight Z-score. Compared with the EMT 7.7-13.0 mm group, the incidences of PTB, LBW and SGA were 5.5% (adjusted odds ratio [aOR] 0.81, 95% confidence interval [CI] 0.33-2.01), 6.4% (aOR 1.44, 95% CI 0.58-3.58) and 7.3% (aOR 1.21, 95% CI 0.53-2.76) in the EMT ≤7.6 mm group, respectively. Similarly, EMT ≥13.1 mm was not significantly associated with risks of PTB (aOR 0.63, 95% CI 0.24-1.65), LBW (aOR 0.57, 95% CI 0.17-1.95) and SGA (aOR 0.73, 95% CI 0.28-1.92). The odds of other adverse neonatal outcomes, including macrosomia, large-for-gestational age and major congenital malformations, did not show significant differences before and after adjustment in both EMT ≤7.6 and ≥ 13.1 mm groups.

CONCLUSIONS

EMT is not independently associated with adverse perinatal outcomes in IUI cycles. This novel finding would provide reassuring information for IUI patients with thin endometrial linings regarding their neonatal health. However, further prospective cohort studies with larger datasets are needed to confirm the conclusion.

Predictive factors influencing pregnancy rate in frozen embryo transfer

PURPOSE

To evaluate the outcomes of embryo transfer (ET) and to identify the parameters influencing pregnancy outcomes.

METHODS

This study included 938 ET cycles involving single frozen and thawed good-quality blastocyst (Gardner grade ≥3BB) between August 2017 and January 2018. The significance of several parameters including endometrial thickness, position of the transferred air bubble, self-evaluation score by physicians, and uterus direction at ET as predictors of clinical pregnancy was evaluated using univariate and multivariate analyses.

RESULTS

Among 938 ET cycles, 462 (49.3%) resulted in a clinical pregnancy. Endometrial thickness was positively associated with clinical pregnancy in a linear trend. Between the variable position of the transferred air bubble and clinical pregnancy rate showed a curvilinear relationship. Clinical pregnancy rate was higher in cases with good self-evaluation score, whereas there was no difference between groups with different uterus directions. Univariate analysis of predictive parameters identified endometrial thickness, self-evaluation score by physicians, and position of air bubbles as significant predictors of clinical pregnancy, of which endometrial thickness and position of air bubbles appeared to be independently related to clinical pregnancy.

CONCLUSION

Endometrial thickness and the position of transferred air bubbles influenced clinical pregnancy in ET cycles.

The correlation between endometrial thickness and pregnancy outcomes in fresh ART cycles with different age groups: a retrospective study

Background

In assisted reproductive technology (ART) cycles in addition to embryo quality, the receptivity of the endometrium plays the main role in clinical outcomes. Endometrial receptivity is necessary to implantation of an embryo, and ultrasound has been established as an appreciated, simple, and non-invasive technique in the evaluation of the endometrial preparation before embryo transfer in fresh in vitro fertilization (IVF) cycles. Debate on the predictive value measuring endometrial thickness before administering human chorionic gonadotropin (HCG) for ovulation triggering in ART is ongoing. In order to explore the impact of endometrial thickness on triggering day on ongoing pregnancy rate (OPR) in ART cycles, we retrospectively analyzed data from 1000 patients undergoing IVF/ICSI cycles.

Results

The data showed pregnancy rate was increased in the endometrial thickness of 8 mm to 11 mm then decreased, and in endometrial thickness (Ent) > 14 mm, pregnancy rate was zero. There were significant differences in endometrial thickness and pregnancy outcomes between different age groups. The pregnancy rate was higher (32%) in 23–30 years old women, and the range of Ent in this group was 6–12 mm. Also, the data showed a positive correlation between Ent with AMH and estradiol levels and the number of COC and MII oocytes and a negative correlation between female age with Ent.

Conclusion

The result showed that Ent on hCG administration day is associated with pregnancy outcomes in fresh IVF/ICSI cycles with different age groups, although some of the clinical parameters may have an effect on Ent. Large studies are needed to make a definitive conclusion.

Sonic Hedgehog, a Novel Endogenous Damage Signal, Activates Multiple Beneficial Functions of Human Endometrial Stem Cells

Local endometrial stem cells play an important role in regulating endometrial thickness, which is an essential factor for successful embryo implantation and pregnancy outcomes. Importantly, defects in endometrial stem cell function can be responsible for thin endometrium and subsequent recurrent pregnancy losses. Therefore, many researchers have directed their efforts toward finding a novel stimulatory factor that can enhance the regenerative capacity of endometrial stem cells. Sonic hedgehog (SHH) is a morphogen that plays a key role in regulating pattern formation throughout embryonic limb development. In addition to this canonical function, we identified for the first time that SHH is actively secreted as a stem cell-activating factor in response to tissue injury and subsequently stimulates tissue regeneration by promoting various beneficial functions of endometrial stem cells. Our results also showed that SHH exerts stimulatory effects on endometrial stem cells via the FAK/ERK1/2 and/or phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways. More importantly, we also observed that endometrial stem cells stimulated with SHH showed markedly enhanced differentiation and migratory capacities and subsequent in vivo therapeutic effects in an endometrial ablation animal model.

The effect of endometrial thickness and endometrial blood flow on pregnancy outcome in intrauterine insemination cycles

Objective:

To investigate whether endometrial thickness and endometrial blood flow on the day of hCG administration is a predictor of intrauterine insemination (IUI) success.

Method:

A cross-sectional prospective clinical study with simple randomized sampling; Patient: 100 women experiencing the IUI cycle; Interventions: a comparison was made between pregnant and non-pregnant patients in terms of the endometrial thickness and pattern as well as the color Doppler flow on the day of hCG administration and also cycle parameters. Main outcome measures: endometrial thickness and patterns as well as the blood flow in color Doppler.

Results:

With the overall pregnancy rate being 38%, it was demonstrated that the endometrial blood flow was significantly greater in the cycle pregnancy obtained on the day of hCG administration, yet it was realized that the endometrial thickness and pattern of sonography did not have any predictive values for endometrial receptivity . In a multivariate analysis, the pregnancy rate was affected by the following variables: the duration of infertility, the women's age, the type number of IUI cycles, the number of injections to stimulate dominant follicles, and the sperm count. In the current study, the variability was realized to be of no predictive values for the IUI outcome, yet the endometrial flow in color Doppler was found to be positively connected with the pregnancy outcome.

Endometrial thickness and IVF cycle outcomes: a meta-analysis

RESEARCH QUESTION

In this meta-analysis, the association between endometrial thickness (EMT) and cycle outcomes after IVF is explored. Associations between EMT and cycle outcomes according to study and individual characteristics were also assessed.

DESIGN

Studies evaluating associations between EMT and pregnancy, implantation, miscarriage, live birth or ongoing pregnancy and ectopic pregnancy rates in individuals after IVF were identified on PubMed, Embase and the Cochrane Library (from their inception up to December 2018). Pooled odds ratios with 95% confidence intervals, calculated using the random-effects model, were used.

RESULTS

Nine prospective and 21 retrospective studies, including a total of 88,056 cycles, were retrieved. The summary odds ratios indicated that women with lower EMT were associated with lower pregnancy rates than those with higher EMT (n = 30, OR 0.61; 95% CI 0.52 to 0.70; P < 0.001). Moreover, the implantation rate in women with lower EMT was significantly reduced (n = 9, OR 0.49; 95% CI 0.32 to 0.74; P = 0.001). Furthermore, no significant association was found between EMT and the miscarriage rate (n = 12). In addition, women with lower EMT were associated with reduced live birth or ongoing pregnancy rate (11 studies, OR 0.60; 95% CI 0.48 to 0.73; P < 0.001). Finally, the incidence of ectopic pregnancy rate between lower and higher EMT showed no statistically significant association (n = 3).

CONCLUSIONS

Lower EMT was associated with lower pregnancy, implantation and live birth or ongoing pregnancy rates.

Management of thin endometrium in assisted reproduction: a clinical practice guideline from the Canadian Fertility and Andrology Society

The impact and management of thin endometrium is a common challenge for patients undergoing assisted reproduction. The objective of this Canadian Fertility and Andrology Society (CFAS) guideline is to provide evidence-based recommendations using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework on the assessment, impact and management of thin endometrium in assisted reproduction. The effect of endometrial thickness on pregnancy and live birth outcomes in ovarian stimulation and IVF (fresh and frozen cycles) is addressed. In addition, recommendations on the use of adjuvants to improve endometrial thickness and pregnancy outcomes are provided.

The association between endometrial thickness and pregnancy outcome in gonadotropin-stimulated intrauterine insemination cycles

BACKGROUND

Intrauterine insemination (IUI) is the first-line treatment for non-tubal infertility. Injectable gonadotropins are often chosen as adjunctive stimulation to promote the growth of ovarian follicles in IUI cycles. The growing follicles produce estrogen, which induces endometrial proliferation and increased endometrial stripe thickness (EST). The association between EST and pregnancy outcome in gonadotropin stimulated IUI is not well studied. The objective of this study is to determine if EST can predict pregnancy outcome in gonadotropin-stimulated IUI cycles.

METHODS

A retrospective review was conducted of all exclusively gonadotropin-stimulated IUI cycles performed between 2012 and 2015 at an academic fertility clinic. Mean endometrial thickness was compared in positive versus negative cycles using Student T-test. Peak EST values were then divided into four groups of < 7 mm, 7.0-10.4 mm, 10.5-13.9 mm, and ≥ 14 mm. Multiple logistic regression analysis adjusted for potential confounders was conducted to assess the impact of peak EST on cycle outcome.

RESULTS

Our sample consisted of 1065 IUI cycles representing 548 patients with a 16.9% clinical pregnancy rate and 20.5% conception rate. No significant differences in mean peak EST were observed between cycles that achieved clinical pregnancy or conception and those that did not. Division of peak EST into four groups showed a non-linear relationship between peak EST and cycle outcome, with highest rates of positive outcomes between 10.5-13.9 mm. The odds of clinical pregnancy and conception increased by 38 and 44% respectively with each subsequent peak EST category up to 10.5-13.9 mm, following which they declined.

CONCLUSION

This is the largest study to date evaluating the effect of peak EST on gonadotropin-stimulated IUI cycles exclusively. The lack of significant difference in peak EST between positive and negative outcomes cycles may be due to the non-linear relationship between cycle outcomes and peak EST. Peak EST in the range of 10.5-13.9 mm was associated with significantly higher conception rates and a trend towards higher clinical pregnancy rates. This non-linearity is likely one of the reasons that EST in isolation was found to be a poor predictor of IUI outcomes, and therefore is not appropriate to be used as the sole indicator for cycle cancellation.

Live birth rates with a freeze-only strategy versus fresh embryo transfer: secondary analysis of a randomized clinical trial

RESEARCH QUESTION

What are the roles of serum progesterone and endometrial thickness as biomarkers in the decision between a freeze-only and fresh embryo transfer in IVF for women without polycystic ovary syndrome (PCOS)?

DESIGN

This was a secondary analysis of a randomized controlled trial including 782 couples who were followed up until the end of the first completed cycle. Couples scheduled for their first or second IVF cycle with a FSH/gonadotrophin-releasing hormone antagonist protocol were randomized to a freeze-only (n = 391) or fresh embryo transfer (n = 391) strategy. The endpoint for this analysis was live birth rate (LBR) after the first embryo transfer.

RESULTS

There was no significant difference in LBR after the first cycle between a freeze-only and fresh transfer strategy. When serum progesterone levels at trigger were in the third quartile (Q3, 1.14-1.53 ng/ml), LBR was significantly higher in the freeze-only versus fresh transfer group (P = 0.01); when serum progesterone was ≥1.14 ng/ml, LBR was significantly better in the freeze-only group (37.4% versus 23.8% in the fresh transfer group; P = 0.004). LBRs in the freeze-only and fresh embryo transfer groups were similar across all quartiles of endometrial thickness, although a small advantage for freeze-only in women with a very thin endometrium could not be excluded.

CONCLUSIONS

Serum progesterone level on the day of trigger may have potential as a biomarker on which to base a prospective decision about whether to use a freeze-only or fresh embryo transfer strategy in women undergoing IVF.

Endometrial but not Ovarian Response is Associated With Clinical Outcomes and can be Improved by Prolonged Pituitary Downregulation in Patients With Thin and Medium Endometrium

The aim of this study is to investigate the effect of ovarian and endometrial response on live birth rates (LBRs) in young normal and high responders and prolonged pituitary downregulation on endometrial receptivity and clinical outcomes in patients with different endometrial thickness. Between January 2013 and December 2017, 9511 patients underwent first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles with age ≤35 years, follicle stimulating hormone < 10 IU/l, and ≥4 retrieved oocytes were conducted. The estradiol (E₂) levels on the human chorionic gonadotropin (HCG) day were classified into 4 groups: group 1 (<3000 pg/mL); group 2 (3000-5000 pg/mL); group 3 (5000-7000 pg/mL), and group 4 (≥7000 pg/mL). Logistic regression analysis was performed to predict the independent variables for live birth. Clinical outcomes between gonadotropin-releasing hormone agonist (GnRH-a) long protocol and GnRH-a prolonged protocol in patients with different endometrial thickness (EMT) were compared. There were no significant differences among the 4 groups in implantation rates, clinical pregnancy rates, and LBRs (P > .05). Binary logistic regression analysis suggested that EMT but not E₂ levels was one of the independent predictive factors of LBRs (odds ratio 0.889, 95% confidence interval, 0.865-0.914, P < .001). The prolonged protocol had significantly higher implantation rates and clinical pregnancy rates in patients with medium (7 < EMT < 14 mm), especially thin endometrium (≤7 mm) compared to short GnRH-a long protocol. Our study showed that endometrial response but not ovarian response was associated with LBRs in young normal and hyper responders. Prolonged pituitary downregulation was an effective treatment to improve endometrial receptivity in patients with medium, especially thin endometrium.

The impact of endometrial thickness (EMT) on the day of human chorionic gonadotropin (hCG) administration on pregnancy outcomes: a 5-year retrospective cohort analysis in Malaysia

Background

Chances of pregnancy in relation to endometrial thickness (EMT) remain elusive albeit some literatures suggest poorer pregnancy outcomes below the threshold of 6-7 mm, notwithstanding others perceive detrimental effect at thicker EMT. We aim to examine the implication of EMT on pregnancy outcomes using a cut-off of 8 mm and further explore for any effect of ‘thick’ EMT in our patient population.

Methods

This was a retrospective cohort study performed for 162 women to assess the associations between EMT on the human chorionic ganadotropin (hCG) trigger day and pregnancy outcomes in infertile patients undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and autologous fresh embryo transfer (ET) in controlled ovarian stimulation (COS) cycles under an assisted reproductive technology (ART) shared-care programme between public and private institutions from January 2012 through December 2016.

The associations between pregnancy outcomes [Total Pregnancy Rate (TPR), Biochemical Pregnancy Rate (BPR), Clinical Pregnancy Rate (CPR), Ongoing Pregnancy Rate (OPR)/ Live Birth Delivery Rate (LBDR), Miscarriage Rate (MR) and Implantation Rate (IR)] and EMT (< 8 or ≥ 8 mm) on the hCG trigger day were evaluated. Besides, the associations between pregnancies outcomes with EMT ≥ 14 mm and ≥ 8 to < 14 mm were further assessed.

Results

We found that the ≥8 mm group had a higher TPR (55.4% vs 21.4%; p = 0.015) and CPR (52.0% vs 21.4%; p = 0.029). However, the BPR, MR, OPR/ LBDR and IR were not associated with the EMT (p > 0.05). All pregnancy outcomes were comparable for ≥14 mm and ≥ 8 to < 14 mm subgroups.

Conclusions

Our findings suggest that EMT < 8 mm on hCG trigger day could adversely affect TPR and CPR in infertile patients undergoing IVF/ICSI-ET. Besides, we also disprove the notion of reduced chances of pregnancy with EMT ≥ 14 mm. The findings are based on completed cycles which each has demonstrated a triple-line endometrial pattern on the hCG trigger day with fresh autologous ET consisted of high-quality morphological gradings. However, our findings are still preliminary to suggest decision for ET transfer, cycle cancellation or adjunctive therapies. Further studies with larger sample size from this geographical region are required to verify the findings.

Gonadotrophins versus clomifene citrate with or without intrauterine insemination in women with normogonadotropic anovulation and clomifene failure (M-OVIN): a randomised, two-by-two factorial trial

BACKGROUND

In many countries, clomifene citrate is the treatment of first choice in women with normogonadotropic anovulation (ie, absent or irregular ovulation). If these women ovulate but do not conceive after several cycles with clomifene citrate, medication is usually switched to gonadotrophins, with or without intrauterine insemination. We aimed to assess whether switching to gonadotrophins is more effective than continuing clomifene citrate, and whether intrauterine insemination is more effective than intercourse.

METHODS

In this two-by-two factorial multicentre randomised clinical trial, we recruited women aged 18 years and older with normogonadotropic anovulation not pregnant after six ovulatory cycles of clomifene citrate (maximum of 150 mg daily for 5 days) from 48 Dutch hospitals. Women were randomly assigned using a central password-protected internet-based randomisation programme to receive six cycles with gonadotrophins plus intrauterine insemination, six cycles with gonadotrophins plus intercourse, six cycles with clomifene citrate plus intrauterine insemination, or six cycles with clomifene citrate plus intercourse. Clomifene citrate dosages varied from 50 to 150 mg daily orally and gonadotrophin starting dose was 50 or 75 IU daily subcutaneously. The primary outcome was conception leading to livebirth within 8 months after randomisation defined as any baby born alive after a gestational age beyond 24 weeks. Primary analysis was by intention to treat. We made two comparisons, one in which gonadotrophins were compared with clomifene citrate and one in which intrauterine insemination was compared with intercourse. This completed study is registered with the Netherlands Trial Register, number NTR1449.

FINDINGS

Between Dec 8, 2008, and Dec 16, 2015, we randomly assigned 666 women to gonadotrophins and intrauterine insemination (n=166), gonadotrophins and intercourse (n=165), clomifene citrate and intrauterine insemination (n=163), or clomifene citrate and intercourse (n=172). Women allocated to gonadotrophins had more livebirths than those allocated to clomifene citrate (167 [52%] of 327 women vs 138 [41%] of 334 women, relative risk [RR] 1·24 [95% CI 1·05-1·46]; p=0·0124). Addition of intrauterine insemination did not increase livebirths compared with intercourse (161 [49%] vs 144 [43%], RR 1·14 [95% CI 0·97-1·35]; p=0·1152). Multiple pregnancy rates for the two comparisons were low and not different. There were three adverse events: one child with congenital abnormalities and one stillbirth in two women treated with clomifene citrate, and one immature delivery due to cervical insufficiency in a woman treated with gonadotrophins.

INTERPRETATION

In women with normogonadotropic anovulation and clomifene citrate failure, a switch of treatment to gonadotrophins increased the chance of livebirth over treatment with clomifene citrate; there was no evidence that addition of intrauterine insemination does so.

FUNDING

The Netherlands Organization for Health Research and Development.

The effect of endometrial thickness on pregnancy outcome in patients with Asherman's syndrome post-hysteroscopic adhesiolysis

Background

Hysteroscopic adhesiolysis anatomically restores the uterine cavity in cases of Asherman’s syndrome (AS); however, the extent of endometrial fibrosis could determine the pregnancy outcome.

Objectives

To determine whether endometrial thickness could influence pregnancy outcome of hysteroscopic adhesiolysis in women with a history of AS.

Subjects and methods

This was a retrospective cohort study that included 41 women who attended Women’s Specialized Hospital, King Fahad Medical City from December 2008 to December 2015, presented with a history of infertility or recurrent pregnancy loss, and were diagnosed with intrauterine adhesions and treated by hysteroscopic adhesiolysis. To analyze the causative factors of AS, history of curettage, miscarriage, postpartum hemorrhage, hysteroscopy, endometritis, and any uterine surgery were recorded. Patients were followed up for 2 years to account for pregnancy. Patients were divided into two groups based on measurement of endometrial thickness in the midsagittal plane at mid-cycle of a menstrual period. Group A consisted of 26 patients with endometrial thickness ≤5 mm, and group B included 15 patients with endometrial thickness >5 mm. The main outcome measures included endometrial thickness and pregnancy outcome.

Results

Group A had significantly (P<0.001) lower pregnancy rates compared with group B (38.4% versus 80%, respectively). Five of 10 pregnancies (50%) from group A miscarried, compared with 1 of 12 (8.3%) pregnancies in group B. This was statistically significant (P<0.001).

Conclusion

Pregnancy rates were observed to be higher when the endometrium was >5 mm in thickness among patients with AS and miscarriage rates may be reduced in this group.

Endometrial thickness on the day of embryo transfer is a poor predictor of IVF treatment outcome

STUDY QUESTION

What is the independent contribution of endometrial thickness (EMT) on day of embryo transfer to achieving an ongoing pregnancy and live birth after IVF treatment?

SUMMARY ANSWER

EMT is a poor predictor of IVF success and has only little independent prognostic value.

WHAT IS KNOWN ALREADY

In a number of previous studies, pregnancy rates have been found to be lower in patients with thin endometrium.

STUDY DESIGN SIZE DUARATION

This is a retrospective analysis of data from two large, randomized phase III studies (conducted in Europe and the USA) comparing s.c. progesterone with vaginal progesterone for luteal phase support. The studies were very similar in design, patient population and outcome, and the study data were combined and analysed on an individual patient level.

PARTICIPANTS/MATERIALS SETTING METHOD

Subjects were infertile patients with an indication for IVF/ICSI, aged between 18 and 42 years, BMI <30 kg/m², <3 prior ART cycles and ≥ 3 oocytes after controlled ovarian stimulation with GnRH-agonist or GnRH-antagonist. EMT was assessed on day of embryo transfer (n = 1401). The association of EMT and ongoing pregnancy rate was determined by comparison of outcomes by quantiles of EMT. The predictive capacity of EMT for ongoing pregnancy achievement was assessed at each millimeter cut-off. Finally, a regression model was built to determine the contribution of EMT among other confounders, such as age and oocyte numbers, on the likelihood of ongoing pregnancy and live birth.

MAIN RESULTS AND THE ROLE OF CHANCE

In univariate analysis, ongoing pregnancy rates correlate to EMT. In patients above a cut-off of ≥9 mm EMT, the chance of pregnancy was higher as compared to patients with an EMT of 3-8 mm (odds ratio (OR) = 1.69, 95% CI: 1.23-2.35, P = 0.001; sensitivity 88.89%, specificity 17.52%, positive predictive value 39.02%, negative predictive value 72.64% and likelihood ratio 1.08). In multivariate regression analysis, after controlling for trial, female age and oocyte numbers, EMT was a statistically significant predictor of live birth (OR = 1.05, 95% CI: 1.00-1.10; P = 0.0351). If EMT indeed is an independent factor affecting outcome, this finding implies that at a baseline live birth rate of 20% an increase of 2 mm in EMT should result in an increase of the live birth rate of ~1.6%.

LIMITATIONS REASONS FOR CAUTION

The independent contribution of EMT to live birth likelihood is small and may result from (undetermined) confounding. The EMT on day of embryo transfer is usually higher as compared to the EMT on day of triggering final oocyte maturation when it is conventionally assessed during routine cycle monitoring. Furthermore, endometrial lining pattern and/or subendometrial Doppler flow have not been assessed and, accordingly, the conclusions of this work are limited to only the thickness of the endometrium.

WIDER IMPLICATIONS OF THE FINDINGS

EMT can be ignored during cycle monitoring of the majority of IVF patients and only the extremes of EMT deserve further diagnostic work-up.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by IBSA. G.G. has received personal fees and non-financial support from MSD, Ferring, Merck-Serono, Finox, TEVA, IBSA, Glycotope, Abbott, Gedeon-Richter as well as personal fees from VitroLife, NMC Healthcare, ReprodWissen, BioSilu and ZIVA. S.T. and B.C. are employees of IBSA.

TRIAL REGISTRATION NUMBER

NCT00827983 and NCT00828191 (clinicaltrials.gov).

Trial registration date

23 January 2009 (NCT00827983 and NCT00828191).

DATE OF FIRST PATIENT’S ENROLMENT

January 2009 (NCT00827983 and NCT00828191).

Ovarian stimulated cycle: not a better alternative for women without ovulation disorder in intrauterine insemination

To explore the related factors on the clinical pregnancy outcome in intrauterine insemination, a retrospective study was conducted on the clinical data of 580 cycles for 301 infertile couples who were treated with intrauterine insemination. The female age, male age, duration of infertility, treatment protocols, endometrial thickness and sperm parameters were compared between pregnant group and non-pregnant group. The results showed that there were statistical differences in female age, duration of infertility and endometrial thickness between the two groups. The pregnancy rate was 19.34% in Group A (female age ≤ 30 y) compared with 10.91% in Group B (female age > 30 y). The pregnancy rate was 18.44% when the duration of infertility ≤ 2 years, which was higher than another group 10.73% when the duration of infertility > 2 years. Group analysis according to endometrial thickness (Group1: < 8 mm; Group 2: ≥ 8 mm and ≤ 12 mm; Group 3: > 12 mm) demonstrated significant differences in clinical pregnancy rate (7.41%, 18.00% and 11.48% respectively). For those infertile female without ovulation failure, the higher clinical pregnancy rates were observed in patients undergoing intrauterine insemination in natural cycle 16.12% when compared with the patients in ovarian stimulated cycles 10.48%. Thus, we demonstrate that the pregnancy rate is related with female age, duration of infertility and endometrial thickness. The ovarian stimulated cycle couldn’t improve the pregnancy outcome for those women without ovulation disorder in intrauterine insemination.

Insufficient Angiogenesis: Cause of Abnormally Thin Endometrium in Subfertile Patients?

INTRODUCTION

This study investigated subfertile patients with abnormally thin endometrium after infertility treatment. As they had adequate serum concentrations of hormones, an endometrial factor for subfertility was suspected.

METHODS

To elucidate the cause of subfertility, endometrial biopsies were taken in each patient in the late proliferative and mid-secretory phases of one menstrual cycle. Endometrial biopsies from women with normal menstrual cycles and confirmed fertility who were undergoing hysterectomy for benign uterine disease were used as positive controls. The tissue samples were investigated for steroid hormone receptor expression and for the proliferation marker Ki-67. Immunohistochemistry was performed with antibodies against the marker molecules for endometrial receptivity - β ₃ integrin, VEGF, LIF, and CD56 (large granular lymphocytes, LGLs).

RESULTS

The steroid hormone receptors for estrogen (E2) and progesterone (P) were expressed normally (at the first biopsy) and were down-regulated (at the second biopsy) within the cycle. Strikingly, all of the marker molecules investigated showed negative or weak and inadequate expression in the mid-secretory phase. Numbers of LGLs remained as low as in the proliferative phase. In contrast, fertile patients were found to express these marker molecules distinctly in the mid-secretory phase.

CONCLUSIONS

It may be hypothesized that a severe deficiency of these angiogenesis-related marker molecules leads to defective development of the endometrium, which remains thin. Deficient angiogenetic development may thus provide an explanation for the endometrial factor that causes infertility. Further investigations will need to focus on identifying the regulating factors that act between steroid receptor activation and the expression of these marker molecules.

Endometrial thickness influences neonatal birth weight in pregnancies with obstetric complications achieved after fresh IVF-ICSI cycles

PURPOSE

Pregnancy-associated complications, duration of gestation and parity are well-known predictors of neonatal birth weight. Assisted reproductive technology (ART) affects neonatal birth weight as well. Endometrial thickness as measured on the day of HCG triggering may therefore impact on the neonatal birth weight.

METHODS

The data of 764 singleton deliveries achieved after fresh transfer between November 1997 and 2014 were collected retrospectively with the intention to analyze the relationship of maternal and neonatal characteristics with endometrial thickness and the possible predictive value of endometrial thickness on neonatal birth weight.

RESULTS

Higher maternal age (p < 0.001), diminished ovarian reserve (p < 0.001), endometriosis (p = 0.008) and hypogonadotropic hypogonadism (p < 0.001) predicted thin endometrium. Neonatal birth weight (p = 0.004), longer duration of pregnancy (p = 0.008), parity (p = 0.026) and higher maternal BMI (p = 0.003) were correlated significantly with the degree of endometrial proliferation. Endometrial thickness strongly predicted neonatal birth weight (p = 0.004). After adjusting regression analysis for maternal age and BMI, parity, neonatal gender and pregnancy duration, endometrial thickness remained predictive for neonatal birth weight in pregnancies with obstetric complications (p = 0.017). In uneventful pregnancies duration and parity are determinants of neonatal birth weight.

CONCLUSIONS

Our findings suggest that endometrial thickness is an additional ART-related factor influencing neonatal birth weight. This finding should be confirmed in large cohort studies.

Ultrasound in Infertility Treatments

Ultrasound (US) is very useful in diagnosing causes of infertility. Pelvic masses, mullerian anomalies, ovarian reserve, and tubal patency can all be assessed using ultrasonographic techniques. US has also proven to be a very useful aid in managing infertility treatments. In this chapter, we review the uses of US in monitoring follicular development, assessing the endometrium during treatment, and as an aid to embryo transfer during in vitro fertilization.

Influence of endometrial thickness on treatment outcomes following in vitro fertilization/intracytoplasmic sperm injection

BACKGROUND

The study was designed to investigate the roles of endometrial thickness (EMT) at the day of human chorionic gonadotropin (hCG) administration on pregnancy outcomes in a large patient population.

METHODS

This retrospective cohort study included 9,952 patients undergoing their first IVF/ICSI with autologous oocytes from January 2011 to January 2015. Patients were divided into three groups based on the EMT (group A:≤8 mm; group B: 9-14 mm and group C:≥15 mm). Live birth rate (LBR), clinical pregnancy rate (CPR), early miscarriage rate (EMR), and ectopic pregnancy rate (EPR) were analyzed. Additionally, the live birth rate was analyzed for patients with single or double gestational sacs.

RESULTS

Significant differences (p < 0.05) were detected in the LBRs (30.38%, 45.73% and 54.55% for groups A, B, and C, respectively), CPRs (38.57%, 55.04% and 64.32%, respectively), and EPRs (5.58%, 3.48% and 2.19%, respectively), with thicker endometrial thickness favoring all three parameters. However, no differences were found in the EMRs among the three groups (15.64%, 13.44% and 13.05%, respectively, p > 0.05). After adjusting for female age, body mass index (BMI) and endometrial pattern, the multivariate logistic regression analysis demonstrated that the associations between EMT and LBR (adjusted OR: 2.645; 95% CI 2.020-3.464; p < 0.01), CPR (adjusted OR 2.693 95% CI 2.012-3.605 p < 0.01), and EPR (adjusted OR: 0.298 95% CI 0.101-0.713; p < 0.05) were significant. Additionally, live birth rates in the double gestational sac group were different (p < 0.05) among patients with different EMT (72.73%, 87.28%, and 87.36%, respectively), whereas no difference was found in the single gestational sac group. In the double gestational sac group, LBR was positively correlated with increasing endometrial thickness only in patients with twin pregnancies but not in patients with singletons.

CONCLUSIONS

Our study shows that endometrial thickness at the day of hCG administration has an effect on LBR, CPR and EPR, with all three parameters increasing with the EMT. Furthermore, successful twin pregnancies are associated with a thicker endometrium.

Endometrial thickness significantly affects clinical pregnancy and live birth rates in frozen-thawed embryo transfer cycles

In order to explore the relationship between endometrial thickness on the day of embryo transfer and pregnancy outcomes in frozen-thawed embryo transfer (FET) cycles, we retrospectively analyzed data from 2997 patients undergoing their first FET cycles from January 2010 to December 2012. All patients were divided into three groups (Group A, ≤8 mm; Group B, 9-13 mm; Group C, ≥14 mm) according to the endometrial thickness on embryo transfer day. Compared with patients in the other two groups, patients with thin endometrial thickness in Group A had significantly lower clinical pregnancy rate (33.4%, 41.3% and 45.4%, p < 0.01) and live birth rate (23.8%, 32.2% and 34.0%, p < 0.01). After adjusting for age, body mass index (BMI), baseline follicle stimulating hormone (FSH) FET protocol and number of embryos transferred, the associations between medium endometrial thickness (Group B) and clinical pregnancy rate [adjusted odds ratio (aOR): 1.39; 95% confidence interval (CI): 1.10-1.77, p < 0.01] and live birth rate (aOR: 1.50; 95% CI: 1.16-1.95, p < 0.01) were significant. We conclude that for patients undergoing FET, endometrial thickness on the embryo transfer day significantly affects IVF outcomes in cleavage embryo transfer cycles independent of other factors.

Endometrial thickness as a predictor of pregnancy outcomes in 10787 fresh IVF-ICSI cycles

This retrospective study assessed the predictive value of endometrial thickness (EMT) on HCG administration day for the clinical outcome of fresh IVF and intracytoplasmic sperm injection (ICSI) cycles. A total of 8690 consecutive women undergoing 10,787 cycles over a 5-year period were included. The 5th, 50th and 95th centiles for EMT were determined as 8, 11 and 15 mm, respectively. Group analysis according to these centiles (Group 1: < 8 mm; Group 2: ≥ 8 and ≤11 mm; Group 3: > 11 and ≤15 mm; Group 4: > 15 mm) demonstrated significant differences (P < 0.001) in clinical pregnancy rates (23.0%, 37.2%, 46.2% and 53.3%, respectively), live birth rates per clinical pregnancy (63.3%, 72.0%, 78.1% and 80.3%, respectively), spontaneous abortion rates (26.7%, 23.8%, 19.9% and 17.5%, respectively), and ectopic pregnancy rates (10.0%, 4.3%, 2.1% and 2.2%, respectively). Logistic regression analyses showed EMT as one of the independent variables predictive of clinical pregnancy (OR = 1.097; P < 0.001), live birth (OR = 1.078; P < 0.001), spontaneous abortion (OR = 0.948; P < 0.001), and ectopic pregnancy (OR = 0.851; P < 0.001). Future research should aim to understand the underlying mechanisms relating EMT to conception, ectopic implantation and spontaneous abortion.

The Impact of Endometrial Thickness on the Day of Human Chorionic Gonadotrophin (hCG) Administration on Ongoing Pregnancy Rate in Patients with Different Ovarian Response

In order to explore the impact of endometrial thickness on hCG administration day on ongoing pregnancy rate (OPR) in IVF-ET cycles, we retrospectively analyzed data from 10,406 patients undergoing their first IVF cycles with standard gonadotropin releasing hormone analogue (GnRH-a) long protocol. Firstly, patients were divided into poor (≤ 5 oocytes), medium (6–14 oocytes), and high (≥ 15 oocytes) ovarian responders based on the number of oocytes retrieved. In each group, patients were sub-divided into three groups according to the endometrial thickness on the day of hCG administration: Group A, thin endometrial thickness (≤ 7 mm); Group B, medium endometrial thickness (8–13 mm); Group C, thick endometrial thickness (≥ 14 mm). (1) For poor responders, OPRs were significantly different in the three endometrial thickness groups (28.57%, 44.25%, and 51.34%; P = 0.008). The association between thin endometrial thickness and OPR was significant after controlling for age, number of embryos transferred by multivariate logistic regression analysis (adjusted OR: 0.408; 95% CI: 0.186–0.898; P = 0.026. Reference = thick endometrial thickness). (2) For medium responders, OPRs were 31.58%, 55.56%, and 63.01% (P = 0.000) in the three groups. Adjusted OR for thin endometrial thickness was 0.284 (95% CI: 0.182–0.444; P = 0.000). (3) For high responders, OPRs were also significantly different in the three groups (28.13%, 52.63%, and 63.18; P = 0.000). Adjusted OR for thin endometrial thickness was 0.233 (95% CI: 0.105–0.514; P = 0.000). For patients undergoing IVF with different ovarian response, a thin endometrium on the day of hCG administration adversely affects ongoing pregnancy rate.